Camera



April 30, 1946` 1 1. w. DOYL ETAL 2,399,476

CAMERA Filed Nov. 27, 1943 9 Sheets-Sheet l ntervolometers -All 1 ATTOR N EYS April 30, 194s. W, DOYLE ETAL 399,476

CAMERA Filed Nov. 27, 1945 9 sheets-sheet 2 280 Sgn@ BY fran/r W1 Sefuayerz f ATTORNEYS pril 30, 1946. l, W DOYLE ETAL 2,399,476

CAMERA Filed Nov. 27, 1943 9 Sheets-Sheet 5 INVENToRs @www/7M f ATroRNEYs April 30, 1946. l. w. DOYLE ET AL CAMERA Filed NOV. 27, 1943 9 Sheets-Sheet 5 April 30, 1946. l. w. DOYLE ETAL 2,399,476

CAMERA A Filed Nov. 27, 1945 9 sheets-sheet e ai ws,

prl 30, 17946. 1 W DQYLE ETAL 2,399,476

CAMERA Filed Nov. 27, 1943 9 Sheets-Sheet 7 Irving [e Alfred Nas ATTORNEYS April 30, 1946. l, W DQYLE ET AL 2,399,476

CAMERA I Filed Nov. 27, 1943 l9 Sheets-Sheet 8 INVENTORS Irl/'i119' WDvlZe ./llfred Nas ATroRNE-Ys l. W. DOYLE ET AL April 3,0, 1946.

CAMERA Filed Nov. 27, 1945 9 Sheets-Sheet 9 Patented Apr. 30, 1946 cama Irving W. Doyle, Massapequa, Allred G. Nash, Richmond Hill, and Frank W. Stcliwagen, Kew N. Y., assignors to Fairchild Camera 'and Instrument Corporation, a corporation of Delaware Application Novembei 21, 1943, serial No. 511,904

(ci. sis-s) llC'iaims.

This invention relates to an aerial camera. One of the objects of this invention is to provide an aerial camera characterized by sturdiness and durability, thus enabling its extended use under a wide variety of conditions. Another object is to provide a camera of this nature capable of dependably photographing terrain with high deiinition and accuracy, while operating at substantial altitudes. Another object is to provide an aerial camera adapted for day or night photography,gwithout the necessity of any modiilcations, additional accessories or lens change. A further object is to provide an aerial camera capable during day time operation of taking a number of successive pictures at regular time intervals. A

A still further object is to provide an aerial camera for night photography which automatically operates through a complete cycle of operation when subjected to the light of a flare. Another object is to provide an aerial camera for night photography wherein the shutter is automatically opened a predetermined amount of time before the flash of light from the flare, and closed a predetermined length of time after the flash. An additional object is to provide an aerial camera, the shutter of which, when the camera is used for night photography, can be opened substantially simultaneously with the emanation of light from the ilare so as to be fully synchronized to take full advantage, of the peak illumination of the flare. Another object is to provide a camera of the above nature which is completely self-contained and capable of operation either locally or remotely. Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described, and

I the scope of the application of which will be indicated in the following claims.

In the drawings, wherein we have shown one embodiment of our invention,

Figure 1 is a side elevation of our camera with a cover plate removed to show an amplifier unit detachably secured to the camera cone;

Figure 2 is a side elevation of our camera withl the magazine removed taken'at 90 from the view shown in Figure 1, a portion of the camera being broken away, and other portions being shown in section to illustrate the structure within the camera cone and within the ampliier unit. This view is taken substantially along the line 2-2 of Figure l;

Figure 3 is a top plan view of the camera case; Figure 4 is an enlarged horizontal section through the shutter taken along the line 4 4 of Figure 2:

` Figure 5 is an enlarged horizontal staggered .section taken along the line 5-5 of Figure 2;

Figure 6 is a greatly enlarged view of the shutter operating and retard mechanism shown at the top of Figure 4;

Figure 7 is a greatly enlarged view of other portions of the shutter operating mechanism shown at the top of Figure 5;

Figure 8 is an enlarged fragmentary sectional view of a portion of the shutter operating mechanism as viewed along the line 8-8 of Figure 6;

Figure 9 is a vertical section taken along the line 9-9 of Figure 5;

Figure 10 is an enlarged fragmentary sectional elevation taken along the line ill- III of Figure 3, portions being broken away to show the operating mechanism of the case drive;

Figure 11 is a horizontal section taken along the line II-il of Figure 10;

Figure 12 is a sectional elevation taken along the line l2+|2 of Figure 10; and,

Figure 13 is a wiring diagram showing the I control system for our camera.

Similar reference characters refer to similar parts throughout the various views of the drawings.

With reference to Figure 1, our camera comprises a main body or case, generally indicated at 20, to the top of which is detachably secured a magazine generally indicated at 2|, and to the bottom of which is secured a cone generally ndicated at 22. Case 20 has secured thereto a main driving motor 23, which is connected through suitable reduction gearing 24 to the case drive mechanism generally indicated at 25 in Figure 3, by means of a detachable coupling rod 26, this rod being wholly disposed within case 2li.

Referring to Figure 2, cone 22 has detachably mounted therein a shutter and lens assembly generally indicated at 21, and the various operating and control mechanisms of the shutter are connected to case drive 25 and control knobs by means of telescopic shafts 2B, 29, 30 and 3i. Cone 22 also has detachably secured thereto an amplier unit generally indicated at 32 (Figure 1) which is adapted to amplify the electrical output of a light-responsive element, such as a photoelectric cell 33 (see also Figure 2). In general, it will now appear that when the camera is used for night photography. a flash of light impressed on photocell u results in an electrical output by the cell, which output is amplified by amplifier 32 to effect operation of shutter 21. Operation of the shutter (as will be pointed out in detail below) results in the automatic actuation of case drive mechanism 25, which rewinds the shutter spring, and through a driving connection 34 (Figure 3) with magazine 2| (Figure 1) winds a fresh supply of hn into the focal plane of the camera, and also automatically sets the shutter for the next exposure.

The structural details and specific operation of magazine 2| (Figure 1) form no part of our present invention, and accordingly it will be noted that the magazine is preferably one containing strip lm capable of being automatically fed from a supply spool and rewound on a rewind spool after each exposure in such a way that each unexposed portion of the film is accurately and securely positioned within the focal plane automatically after each exposure. Advantageously magazine 2| may correspond to the magazine shown in the copending application of Irving W. Doyle, Serial No. 462,267, filed October 16, 1942. It might be noted that inasmuch as magazine 2| is readily detachable from case 20, extended continuity of successive photographs is readily attainable, merely by replacing a magazine containing an exposed film with one containing unexposed film.

Referring now to Figure 3, camera case 20 comprises a relatively heavy and rigid frame formed by front and back plates 35 and 36, respectively,

n and side plates 31 and 38. All of these plates are `preferably integrally joined to form a rigid support for the magazine and cone, assemblies. Motor 23 is preferably detachably secured to side plate 38 and carries contacts (not shown) which engage suitable contacts (also not shown) on the side plate when the motor is attached. Thus the motor may include a threaded stud 39 which projects through a hole in side plate 38 on which may be threaded a wing nut 40 to attach the motor to the case. Reduction gear 24 includes an output shaft 4| which also extends through case side 38 for connection with one end of shaft 26. The other end of shaft 26 is provided with a connection 26a adapted to connect with the input shaft 42 of case drive 25.

Case drive 25 is preferably a unitary assembly which may be detachably mounted within case 20 adjacent side 31 thereof in any suitable fashion, as by screws 43, which extend through flanges 44 on the case drive cover plate into front and back plates 35 and 36. The case drive includes a main drive shaft 45 (Figure 10) one end 45a of which is connected through suitable gearing 46 to the input shaft 42 of the case drive (see Figure 3). The other end 45b of case drive shaft 45 (Figure 10) carries an axially movable toothed coupling 41 which is pressed to the right, as viewed in Figure 10, by a spring 48 coiled on shaft end 45h, to mesh with another coupling 49 (Figure 3) secured to a crank shaft 50. Crank shaft 50 extends through front 35 of the camera case and has secured to its outer end a crank which may be rotated clockwise, as viewed from the left-hand side of Figure 3. to effect hand operation of case drive 25 in the event of a power failure or breakdown. of motor 23. So far as described, case drive 25 is generally similar to that shown in United States patent to S. M. Fairchild, 1,817,182.

To the front plate 35 of case 2n :fs secured a diaphragm and shutter speed adjusting mechanism generally indicated at 52, including a knurled setting disc 51 mounted on a shaft 64 and secured to a gear 55 which meshes with a gear 56 attached to a shaft 51. Thus when disc 53 is rotated, shaft 61 is also rotated. It might be noted that shaft 51 may be rotated either locally by manipulation of disc 53, or remotely by any suitable mechanism (not shown). Shaft 54 may be rotated by a knurled disc 54a. Shafts 54 and 51 (Figure 2) are respectively detachably secured to the upper ends of telescopic shafts 3l and 30. The lower ends of these shafts are respectively provided with sockets 6l and 60 connectible respectively with the shafts of the shutter speed control mechanism and the diaphragm control mechanism to be described hereinafter.

The case drive 26 (Figure 10) includes mechanism to be described below, through which a shaft drives a coupling 63 by way of gears 64 and 65 connected respectively to the shaft and a. stud 66 which carries the coupling. lCoupling 63 (Figure 2) is detachably connected to shaft 26, the lower end of which is detachably connected to a coupling 68. This coupling 68 is, as will be described, connected to the shutter operating mechanism, and when operated by the case drive winds the spring which opens and closes the shutter leaves. This operation of the shutter, as also will be described, actuates a coupling 61 which is detachably connected to the lower end of shaft 29, the upper end of which is connected to a coupling 69 connected to a shaft 10 (Figure 11) mounted in case drive 25. As will be described, rotation of shaft 10 causes certain contacts in the case drive to close energizing motor 23 (Figure 3) to drive the case drive through another cycle of its operation, in the course of which the shutter spring referred to is rewound It will accordingly appear that case drive 25 comprises instrumentalities by which the various mechanisms which comprise the `shutter assembly 21 are operated- As shown in Figure 10, the main shaft 45 in case drive 25 has connected thereto a gear 1I which meshes with a larger gear 12 mounted on one end of a shaft 13 journaled in a suitable boss 14 on the housing of the case drive. On the other end of shaft 13 is a bevel gear 15 which meshes with a larger bevel gear 16 mounted on a shaft 62 (Figure 12). The upper end of shaft 62 has secured thereto a spur gear 11 which meshes with another spur gear 18 (Figure 10) fastened to a stud shaft (not shown) rotatably mounted in the case drive housing. The exterior end of this stud shaft has attached thereto the driving connection 34 which may conveniently take the form of a tongued disc by which the film magazine 2| (Figure 1) is operated as described above. The several gears within the case drive 25 (Figure 10) just described, are so proportioned that one revolution of shaft 62, i. e. one operative cycle of the case drive, effects one cycle of opera tion of the film magazine when driven by the driving connection or slotted disc 34.

As noted above, operation of shutter mechanism 21 (Figure 2) rocks coupling 61 which in turn, through connecting rod 29, rocks coupling 69 and accordingly shaft 10 (Figure 10). The rocking of this shaft, which is also shown in Figure 11, occurs as the shutter opens and closes and, being connected to an arm 19, rocks this arm counterclockwise, as viewed in Figure l1. Arm 19 is connected by a link 8|) to a dog 8| pivotally mounted on a stud shaft 82 secured to the housing of case drive 20, and this dog includes a tooth 63 which when in its upper position, l. e. the Flg -ure 11 position, engages with a tooth 84 formed on the upper end of a latch plate 85. This latch plate is pivotally mounted on shaft 'I8 and is under a constant counterclockwise bias by a spring 88, one end of which is fastened to the upper end of the latch plate, and the other end of which is fastened to a boss 81 extending from the case drive housing. Thus, it will appear that when the camera shutter is operated, shaft 10 is rocked to disengage teeth 83 and 84 of the dog and latch plate respectively, thus permitting spring 86 to rock latch plate 85 counterclockwise. This movement of the latch plate causes the case drive to be reset in a manner to be described.

As described above, gear 84 is driven by shaft 82 (Flgures'll and 12). On this shaft is loosely mounted a sleeve 82a (Figure 12) to which is secured a driving ratchet 88. -On the lower end of shaft 52 are a pair of cams 89 and 90 disposed on opposite sides of gear 54 and fastened thereto. A driving pawl 9| (Figure 11) is pivotally mounted on cam 89, and on the same pivot is a control dog 92. A spring 93 has its opposite ends fastened respectively -to the driving pawl and controlling dog to hold them normally in the relative positions shown in Figure 11, in which the stud 94 on the pawl (the stud to which spring 93 is attached) bears against an arm 95 on the dog. In this position the tail 95 of the dog rests against a lug 91 on an extension 98 of latch plate 85 to hold the pawl out of engagement with driving ratchet 88. A spring 99 has one end connected to cam 89 and its other end connected to another arm on dog 92 so that when latch plate 85 is rocked counterclockwise by spring 85, lug 91 on the latch plate is disengaged from tail 98 of the dog, and spring 99 rocks the dog and pawl assembly clockwise. thus bringing pawl 9| into engagement with ratchet 88. If the ratchet 88 is rotated clockwise, as viewed in Figure l1, shaft 82 is also rotated by reason of the driving connection formed therebetween by driving pawl 9| and cam 89. Of course, when shaft 82 is rotated, gears 84 and 11, which are pinned to the shaft, rotate, the former to tension the shutter spring, as will be described, and the latter to operate the magazine as described above.

As shown in Figure 11, latch plate 85 includes an upstanding lug' |0| which, when the latch plate rocks counterclockwise upon shutter operation, as described, engages a movable contact |02 and forces it into engagement with another contact |03. Engagement between these contacts establishes the circuit in which motor 23 (Figure 3) is connected to energize the motor and accordingly drive the case drive. As cam 90 (Figure 11) rotates clockwise, its surface 90a rocks a spring-biased arm |04 counterclockwise to cause engagement between normally open con-4 tacts |05 and |06. These contacts are connected in parallel with contacts |02 and |03 and accordingly maintain the case drive motor energized when contacts |02 and |03 separate, by reason of clockwise movement of latch plate 85 prior to theend of the operative cycle of the case drive. Cam 89 also includes a surface 89a which, as the cam rotates clockwise, engages a pin 85a extending from latch plate 85, and forces the latch plate clockwise against the bias of spring 85. When the latch plate has been rocked sumciently its tooth 84 engages with dog tooth 83 so that the latch plate is locked in the position shown in Figure 11. During this clockwise movement of the latch plate, contacts |02 and |03 open, but as the operative cycle of the case drive is not complete-at this point, the case drive continues to be driven by its motoras contacts and |88 are still closed. These contacts remain closed until arm |84 is permitted to rock clockwise, by

reason of the follower on its end riding into a low spot on cam 80. When this occurs, the cycle of the case drive is complete and the circuit to Yits driving motor is broken. As noted above, the

case drive is not only operating the film magazine, but is also winding theshutter spring, As the shutter spring is of substantial strength, cam 99 is provided with a stop 90c which, by reason of its inability to pass the follower on the end of arm |84 in counter-clockwise direction prevents reverse movement of the cam and accordingly the case drive from the driving force exerted by the shutter spring. Cam 89 is also provided with a stop 89a which coacts with ya pin |81 on a spring-biased lever |08 to prevent counter-clockwise movement of the cam by the shutter spring.

It will now appear that the cycle of operation f of case drive 20 is initiated by operation of the shutter, and that in the course of the operative cycle the film magazine is operated and the shutter spring is retensioned automatically without either being able to overrun, thus precluding damage to the magazine or wastage of film or overtensioning of the shutter spring.

Referring now to Figure 2, the cameral cone 22 includes a recess |09 within which amplifier 32 is secured and the base of this recess, together with other suitable bosses formed about the inner wall of the cone provide mounting surfaces on which the shutter mechanism 21 may be detachably secured.

Shutter mechanism 2l includes a casing |l0 within which are disposed the mechanisms which control the opening and closing of the shutter leaves, the position of the iris diaphragm and the retard mechanism which controls the shutter speed. Casing 0 has secured to its upper side a housing in which are disposed other shutter control mechanisms to be described, and to the bottom of casing ||0 is detachably secured a lens mount ||2 in which suitable lenses are disposed.

'I'he mechanisms in casing ||0 are better shown in Figures 4, 6, '7, and 8, and We will first describe the mechanism which opens and closes the shutter leaves. We have mentioned above the spring which when under tension and released opens and closes the shutter leaves. This spring is shown at ||3 in Figure 8, having its upper end connected to a cup ||4 and its lower end to a cup ||5. The spring and cups are disposed about a shaft H5, the lower cup being directly connected thereto. Upper cup ||4 is loosely mounted on the upper end of shaft IIB and is connected in any suitable manner to coupling 68. Hence it will appear that when lower cup 5 is held against rotation, as will be described, operation of the case drive 20 (Figure 2) rotates coupling 58 so that when the case drive finishes its cycle of operation, spring 3 (Figure 8) is wound. Lower spring cup ||5 includes a projection ||1 which extends outwardly of the cup'to a point where it can be engaged and held, as shown in Figure 7, by a lug ||8 secured to the armature I9 of a holding magnet generally indicated at |20. When magnet v|28 is energized, its armature |19 is in the position shown in Figure 7. Hence, projection ll'l of the spring cup is held against rotation. When, however, the magnet is deenergized, spring H3 (Figure 8) drives projection ||1 past lug |I8 and as cup I|5 is attached to shaft I|6, the shaft is rotated to effect opening and closing of the shutter leaves.

The lower end of shaft I I6 extends through the top I |||a of casing I I0 and has secured to it below the casing top a cam |2|. As shown in Figure 4, cam |2| is connected by a link |22 to a bell crank |23, and the other end of this bell crank is connected to one of the several shutter leaves |24. 'I'hese shutter leaves may be interconnected in the manner shown in United States Letters Patent 1,626,032 to S. M. Fairchild.I Thus, when cam |2 rotates once, shutter leaves |24 are opened and closed by the driving effect of the linkage comprising link |22 and bell crank |23. l

Cam I2| (Figure 6) is automatically stopped at the end of one rotation, and the shutter is automatically reset for a subsequent operation. To this end we provide a bifurcated lever |25 pivoted on the top |I0a of casing as at |26. Lever |25 includes a follower or reset arm |21 and a stop arm |28. These two arms are shown in Figure 6 in the position wherein stop arm |28 engages an abutment |2| a on cam |2| to stop rotation of the cam at the end of the shutter operation. During the automatic resetting operation of the shutter, and also as shutter spring |3 (Figure 8) is rewound, lever |25 (Figure 6) is rocked clockwise in order to clear stop arm |28 from cam stop 2 |a to prepare the shutter for a subsequent operation, it being noted that magnet (Figure 8) is reenergized during the resetting operation so that engagement between projection ||1 of the lower spring cup ||5 and lug I|8 on the magnet armature |I9 prevent rotation of cam |2| (Figure 6) which would otherwise occur by reason of the separation of stop arm |28 and cam stop |2|a. This clockwise rocking of lever is eiected by a reset lever generally indicated at |29. This lever comprises a link |30 connected to the lower end of a rod |3I (see Figure 8) which extends upwardly through casing top I|0a and through the top of housing III. The other end of link |30 (Figure 6) is pivotally connected to a link |32 connected as by a spring |33 to a link |34 pivoted at |35 to casing I I 0. With the parts in the position shown in Figure 6, a hook portion |34a in link |34 engages a pin |36 projecting from lever |25 and a surface I 32a of link |32 rests against a pin |31 also carried by lever |25. These parts operate in a manner specifically described in Sherman N. Fairchilds Patent 1,626,032 to effect shutter operation.

iAs shutter spring ||3 (Figure 8) is rewound, upper spring cup I I4 rotates. Formed on the upper portion of spring cup ||4 is a cam |38 which engages the free end of a lever |39 as it rotates with the spring cup. The other end of this lever is connected to shaft 3| and accordingly the shaft is rocked as the free end of lever |39 rides over cam |38 t0 reset the trip lever |29.

The upper end of shaft 3| (Figure 8) which extends through the top of housing vhas connected thereto an arm |40 the upper end of which carries a pin I4I. This pin is connected by a spring |42 to a stationary pin |43 fastened to the top'of housing so that when the free end of lever |39 drops 01T the high spot of cam |38 at the end of the winding cycle, spring |42 pulls arm |40 in a direction to rock shaft |3| oppositely to the direction in which it was rocked by cam |33. This reverse action of shaft |32 is transmitted to reset lever |29 (Figure 6), causing the lever to disengage stop |28 from cam stop |2|a.

As has been noted above, the case drive 20 (Figure 10) is automatically reset during opening and closing of the shutter. This is effected as follows: as lower spring cup I I5 (Figure 8) rotates during shutter operation, it rotates a cam |44 and accordingly a cam lobe |45 (Figure 7). Projecting into the path of this cam lobe is the curved end |46 of a. lever |41 (see also Figure 8) fastened to a shaft |48, the lower end of which is rockably mounted in top ||0a of casing |I0. The upper end of shaft |48 projects through the top of housing and is connected to the coupling 61 which, as shown in Figures-2 and 10, is connected by rod 29 t0 coupling 69 and accordingly to shaft 10 which operates dog 8| (Figure 11). Thus it will appear that operation of the shutter causes, through thetrain of mechanisms comprising cam |44 (Figure 8) lever |41, shaft |48, coupling 61, rod 29 (Figure 2), coupling 69 (Figure 10) shaft 10, and dog 8| (Figure 11) release of latch plate 85 and engagement of contacts Il'l and |03 to effect operation of case drive 20 as hereinbefore described. Lever |41 is held in contact with cam |44 by spring 32| one end of which is fastened to a hole in lever |41 and the other end to a pin in casing I0.

Although shutter 21, as described above, is capable of a speed of 1/150 of a second or more, such high shutter speeds are used for only daylight operation of the camera. When the camera is used for night photography, it is sometimes necessary to use a substantially low shutter speed, for example, a speed as low as 1/5 of a second. To this end, we have provided a. retard mechanism which is shown in Figures 4, 6, and 8. As shown in Figure 6, a segment |49 is pivotally mounted on a stud |50 secured to and extending downwardly from the top of casing I|0. Segment |49 is provided with a lobe |5| adapted to be engaged by a cam |52 secured to the bottom of shutter cam or crank |2| during the rotation thereof. Engagement between cam |52 and lobe |5| rocks segment |49 counterclockwise, as viewed in this figure, against the bias of a spring |53, one end of which is fastened to a pin |54 projecting from the segment, and the other end of which is fastened to a pin |55 secured to the top of casing 0. Segment |49 is also provided with a number of teeth |56 which coact with the points of an escapement pallet |51 pivotally mounted on a stud |58 fastened to the top of casing ||0. It will now appear that after cam |2| has rotated approximately at which point the shutter leaves are wide open, cam |52 strikes segment lobe |5| and the speed of rotation of cam |2| is accordingly limited to the rate of escapement between segment teeth |56 and the points on pallet |51.

To attain a still lower shutter speed, we have provided an additional segment |59 pivoted on pin |58 and provided with a lobe |60 adapted to be engaged by a boss |6| carried by segment |49. Segment |59 has teeth |62 which coact with the points of an escapement pallet |63 pivoted on a pin |64 secured to the casing. Thus when boss |6| on segment |49 engages segment lobe |60 of the second segment |59, the rate of movement of the rst segment |49 is accordingly `further reduced by an amount proportional to the rate of escapement between segment teeth |62 and escapement pallet |63.

From the above it will appear that the amount of delay imparted to rotation of shuter cam or crank |2| is a function of the period of engagement between cam |52 and segment lobe 5|. Accordingly, to provide a wide selection of shutter speeds. we have provided an adjusting mecha- Aa shoulder |1.0 adapted to engage pin |64 on segment |48 and also has a surface |1| adapted to engage a pin |12 fastened to segment |58. Pin |12 also comprises an anchor for one end of a v spring |13, the other end of which is anchored by a pin |14 fastened to a lug |16 extending from the wall of casing H0. In passing, it is noted that spring |13 constantly biases segment |58 counterclockwise as viewed in Figure 6.

It will now appear that as plate |65 is pivoted clockwise so that its shoulder |10 engages segment pin |54 and its surface |1| engages segment pin |12, segment |48 is rocked counterclockwise while segment |58 is rocked clockwise. Thus segment |48 may be pivoted to such an extent by this movement of plate |65 that its lobe |5| is moved out of the path of cam |52. Of course when this cam and segment lobe do not engage, there is no retard imparted to the operation of the shutter. Conversely, as plate |65 is pivoted counterclockwise, spring |53 draws segment |48 clockwise to move its lobe |5| into the path of cam |52, while spring |13 pivots segment |58 counterclockwise. Hence, by selecting the position of plate |65, the period of engagement between cam |52 and segment lobe |5| can be determined and accordingly the desired shutter speed can be selected.

Plate 65 is set to the desired position by means of link |68 (Figure 4) the left-hand end of which, as viewed in this figure, is pivotally fastened to one arm of a bell crank |16. The other arm of this bell crank is secured to one end of a spring |11, the other end of which is fastened to a lug extending from the wal1 of casing |0. Bell crank |16 is fastened to one end of a shaft |18 which extends upwardly through the top of casing ||0 (Figure 2) where its upper end carries a lever 400 having an arm 40|. Lever 400 is biased by spring |11 so that arm 40| is normally in engagement with a cam 402 fastened to a shaft 408 the upper end of which is connectable with coupling 6| on connecting rod 3|. As noted above, this rod is controlled by the manipulation of disc 54, thus to set the shutter speed control mechanism. Abp fastened to shaft 403 is a detent plate 48,4

which coasts with a springv urged bau nl. which' rides into notches formed in the plate atheyregister with the ball. These notches are arranged as to number and position in accordance with the variety of shutter speeds desired. Thus the shutterlcan be expeditiously set for the desired speed of operation.

Preferably our shutter 21 (Figure 4) is provided with a conventional iris diaphragm which accordingly includes a gear segment |18 which meshes with a gear |60 fastened to a shaft |8| secured in and extending through the top of casing ||0 (see Figure 9). To the upper end of this shaft is secured a small gear |62 which meshes with another gear |83 secured to a stud shaft |84 pivotally mounted in a boss |85 extending upwardly from the top of casing H0. The upper end of stud shaft |84 (Figure 2) is connectable to socket 60 on the lower end of rod 80 which may be manipulated as hereinbefore described by disc 53 (Figure 3) to rotate shaft |64 and accordingly shaft 6| (Figures 9 and 4). thus to rotate gear |60 and swing segment |18 to adjust the iris diaphragm.

As indicated hereinabove, uur camera is well adapted for both dayl and night photography. Night photography, particularly under conditions of modern warfare, in many instances necessitates the use of flares which burn with explosive effect over an extremely minute fraction of a second and have a peak illumination of an even smaller fraction of a second. In order to utilize this peak illumination, it is accordingly necessary that the camera shutter be open when the illumination is at its maximum, and it is to this end that we have provided the holding magnet |20 briefly referred to hereinabove. As noted above, after the shutter spring ||3 (Figure 8) has been rewound, stop arm |28 (Figure 6) is `moved away from its stopping position shown so that the only thing that restrains the spring from operating theshutter is the engagement between projection ||1 of the spring cup and lug ||8 which is held in the position shown when the magnet |20 is energized. Thus, if the magnet is rapidly vdnergized, there is only an inappreciable delay in the start of the shutter operation. In reducing this delay to a minimum, we have provided magnet |20 having structure and 'characteristics now to be described, and a system of rapidly deenergizing the magnet which will -be described later.

Magnet |20 is shown in Figures 5, '1, and 8 and comprises, as shown in Figure 8, a. casting |86 within which are disposed vcores |66 and coils |81. Cores |86 are made up of a number of U-shaped laminations stacked to the desired height to form a U-shaped core, the legs of which are disposed respectively within the two coils |61. The cores and coils are clamped in place within casting |86 by suitable clamping strips |88 fastened to the casting by screws |88 (see Figure 1). Preferably the pole faces of the core are ground flat to even up the variations between the many laminations.

Casting |85 (Figure 8) includes ears |88 and |8| which pivotally receivel the ends of a shaft |82. The legs |83 and |84 of a U-shaped bracket |85 are loosely carried by shaft |82 and to the bracket is riveted the armature ||8. This armature also consists of a suitable number of flat preferably rectangular laminations which are forced in" between the two sides of a channel shape-:which formsthe top of bracket |85 and then ground to remove inequalities. Preferably the armature assembly is chromium plated after `assembly as is also the magnet body. The rivets |88 and |81 which fasten the armature to the bracket extend through the sides of the channel shape and through the laminations which comprise the armature, thus holding the armature and bracket together in tight, unitary assembly. Extending through the channel shaped sides and armature ||8 is a loosely fitting pin |88 fastened at its left-hand end, as viewed in Figure 8, to a. collar |88 which is pinned to shaft |82. As noted above, bracket legs |83 and |84 are also loosely fitted on shaft |82, and this loose t, together with the loose fit of pin |86 in the armature. is provided so that the armature may float slightly in order to seat evenly against the pole faces |66a (Figure 7) of the magnet core |86. Also secured to shaft |82 (Figure 8) is a collar 200, and it is from this collar that lug ||8 extends.

Magnet |20 is preferably so adjusted that a gap on the order of .005 inch to .010 inch exists between armature ||8 and the pole faces when the lug I|6 just rests against the spring cup pro- .iection II1. The relationship between lug Ill and spring cup projection I|1 is such that when magnet |20 is energized to attract amature I|0 and thereby close the above-mentioned gap to zero, lug IIB cams projection ||1 backward and accordingly rocks shaft IIB and shutter cam |2| (Figure 6) suiciently to back cam stop |2|a away from stop arm |20 thus toiacilitate movement of the stop arm out of the path of stop I2 I a as heretofore dcribed.

As shown in Figure 8, a light spring 20| is coiled about a part of shaft |32 and has its ends so fastened to different parts of the magnet that its bias returns armature III into engagement with the pole faces after projection I 1 has been swept past lug IIB, thus returning the armature into position for immediate attraction by the magnet upon reenergization thereof.

As noted hereinabove, ampliiier 32 (Figure 2) constitutes a unitary assembly which may be detachably mounted on cone 22. Accordingly we provide a mounting platform or bracket generally indicated at 202 (Figure 2) which is iastened at its upper end to cone 22 within the cone recess by screws 203 and at its lower end by screws 204 (Figure 1). Bracket 202 supports the various elements of amplifier 32 and accordingly includes a lower platform 205 (Figure 2) having a downwardly extending plate 208 (Figure l) on which is mounted a socket 201 in which tube 33 is mounted. The photoelectric tube, as shown in Figure 2, is accordingly disposed adjacent an opening 208 in the lower part of cone 22 and at the smaller end of a shield 203 fastened to the cone and extending through opening 200. Thus the photoelectric tube is shielded from all light other than that entering the shield or cone 209. Preferably We provide a shutter 2|0 (Figure 1) which is movable between the full and dotted line positions shown in this ligure to shield from or expose the photoelectric tube to light entering cone 209. As shown in Figure 2, amplifier unit 32 is preferably provided with a cover plate 2II detachably fastened to struts 2|2 extending from cone 22.

To facilitate the electrical connection of amplifier unit 32 to the electrical system oi' the camera, the various electric responsive devices of the amplifier are wired to a suitable number of contacts, such as contact 2|3, secured to the upper part of bracket 202, and these contacts engage with other contacts, such as contact 2|4. mounted on the camera cone 22. Through the provision of these registering contacts, it is unnecessary to provide exterior wiring, sockets or other protruding electrical connectors. In the wiring diagram shown in Figure l2, these contacts or terminals are designated A-F.

As shown in Figure 13. power is supplied to the circuit from a socket 2|5 which is connectaole with the airplane power supply and the amplifier unit is connected to the socket. 'I'he amnliner unit includes a motor generator generally indicated at 2I6 comprising a motor 2I1 to which is coupled a generator 2|0. Motor 2|1 is connected to terminals A and B bv leads 2| 9 and 220, respectively. The negative side of generator 2I0 is connected to ground by a lead 22|, while a leed 222, which supplies vacuum tubes 223 and 224. is connected to the positive side of the generator. Photoelectric tube 33, shown in the upper left-hand corner of the diagram, has its anode 33a connected by a lead 225 to a suitable number of series resistances which in turn are connected to a terminal 223 connected by lead 222 to the andere positive side of generator 2I3. Cathode 33c of the phototube is connected by a lead 221 through a high resistance 228 to ground. The phototube cathode is also connected by lead 221 to a condenser 223 in turn connected by a lead 230 to one side of a sensitivity control device 23|, the control arm 23|a oi which is connected by s shielded lead 232 to the control grid 233 of vacuum tube 223. A

Power is supplied from generator ZIB to vacuum tube 223 by way of lead 222 and terminal 226 to a terminal 234 which is connected by a lead 235 to one side of a resistance 236. The other side of this resistance is connected by a lead 231 to the plate 238 of vacuum tube 223. The cathode 239 of the vacuum tube is connected by a lead 240 to a terminal 24I and thence through a resistance 242 to ground.

It will now appear that when light from an exploded flare strikes the cathode of phototube 33 current flows from the anode to the cathode of the tube and thence through lead 221 and resistance 222 to ground, with the result that the terminal 221a at the top of the resistance has a positive potential. This, in turn, through the coupling of condenser 229, eil'ects a positive bias of control grid 233 of tube 223. This positive bias allows more current to flow from the generator to tube 223 through resistance 233, causing a voltage drop at terminal 235a at the top of resistance 238. This terminal 23Go is coupled through a condenser 243 by a lead 244 to a terminal 245, the terminal in turn being connected through a resistance 245 to ground. Terminal 245 is also connected by a lead 241 to the control grid 248 of vacuum tube 224. Thus it will appear that upon a voltage drop at terminal 230i: a minus potential i5 created at terminal 245, causing control grid 243 to have a negative bias. This negative bias stops the ilow of current through vacuum tube 224 in a. manner and for a purpose to be described.

Generator 2|3 supplies power to vacuum tube 224 as follows: lead 222, terminal 220, filter choke 243, lead 250, terminal 25|, lead 252, terminal C, lead 253, coil |31 of holding magnet I2l, lead 255, movable contact 255, stationary contact 251, lead 258, terminal E, lead 259, stationary contact 250, movable contact 25| lead 202, tube plate 253, tube cathode 264, and lead 265 to ground. The characteristics of tube 224 are such that when generator 2 I3 is operating, current ilows through the tube so that holding magnet |20 is energized, thus holding shutter cam |2| against rotation, as hereinbei'ore described. When, however, the

phototube output is amplified. as described, and

impressed as a negative bias on tube 224, current immediately ceases to flow through tube 224, re-

sulting in immediate deenergization of holding magnet |20, and accordingly immediate release of shutter cam |2|. Thus it may be seen that in an almost immeasurably small amount of time following the explosion oi the flare, the camera shutter operates. y

Itmight be noted that terminal A is connected to ground across the filament X-X of tube 223, and Y-Y of tube 224 to supply these filaments. It should also be noted that a main switch 2li is interposed between socket 2|5 and the connections to the amplifier unit by which the entire system may be turned ofi'.

When the camera circuit is first turned on, vacuum tube 224 is in no condition to conduct current, as it takes an appreciable amount oi' time for lts filament to heat up. Of course ing this time no current can pass from the plate 288 to cathode 264, and consequently holding magnet |28 would bedead. This, in turn, would permit the shutter to trip as faste as it could be wound, and each time it was wound it would trip the case drive, start the motor, rewind the camera, and trip all over again. To preclude this an auxiliary path is provided for the current. Instead of passing from contacts 268 and 26| through vacuum tube 224 to ground, as described,

`the current from7 these contacts through a pair-ofcontacts 281 and 268, through a resistance 268 to ground, thus permitting' magnet coil |81 to be energized, even though tube 228 current which flows through holding magnet |28.

When the camera is used during the daytime, a device known as an lntervalometer is used. This is a device comprising a timing mechanism driven by anv electric motor, `and while we have not shown it in the drawings, it is suicient to note that this device is preferably located convenient to the operator who controls the operation of the camera. Thus the intervalometer is connected to the camera through a three pole socket 288 shown at the right central portion of Figure 12, having contacts A, B, and C. 'I'he intervalometer driving motor gets its power from the A and B contacts, and the camera is tripped by closing a contact within the intervalometer which connects contacts B and C. Contact C is connected by a lead 28| to terminal F, in turn connected by a lead 282 to the coil 288 of the trip relay generally indicated at 284. The other end of this relay coli is connected by lead 286, terminal 281, lead 288 and terminal B to socket 2H the other side of socket 2 I5 being connected by lead 289, main switch 266 and lead 298 to contact B of the intervalometer socket 288. Thus when this circuit is closed, relay trip coil 288 is energized, separating contacts 268 and 26| and accordinglv breaking the circuit through holding magnet |28 thus to trip the shutter. If desired, a manual tripping button 29| may be used to trip the shutter in the same manner. This manually actuated button 29| is preferably located on the camera case (see Figure 1).

Under certain circumstances, it is desirable to make a time exposure. To this end we have pro,-

Avided still another intervalometer (not shown) generally similar to the one referred to above, and also preferably located convenient to the camera operator. This second intervalometer is connected to the camera through a three pole socket 292 and gets its power from the A and B contacts of socket 292. When this intervalometer is turned on the current which energizes its driving motor flows through the coil 298 of a cutout relay generally indicated at 294 at the upper central portion of the diagram. One end of this relay coil 298 is connected by a lead 295 to lead 288 by terminal 281 and thence to post A of the source socket 2li. The other side of relay coil 298 is 288 and accordingly to post B of the source socket lcuit and prevents the camera from tripping when a flash of light hits the photocell.

This second-mentioned intervalometer, when operating, also delivers apulse to the bomb rack (not shown) on the airplane, wherein the flares are stored, to release a flare, and then alter a certain number o! seconds closes a connection from terminal B of socket 282 to terminal C thereof. This connection is timed to close a certain number of seconds before the iiare is due to ignite.

vThe making oi' this connection between contacts B and C of socket 282 permits current to fiow from post C through a lead 882 to one side of a coil 888 of a time exposure solenoid generally indicated at 884. The other side of coil 888 is connected by a lead 885 by way of contacts 886 and 881 and a lead 888 to a lead 889 going to post A of source socket 2li. As the other side of this socket is connected to post B of intervalometer socket 292, the circuit to the time exposure' solenoid 884 is completed when posts B and C of intervalometer socket 282 are connected.

When the time exposure solenoid 884 is energized, its plunger 8|8 is moved to the left, as viewed in Figure 13, causing contacts 256 and 251 to separate, thus brealdng the circuit to holding magnet |28 which permits shutter cam |2| to start to revolve, as hereinbefore described. Also, this movement of solenoid plunger 8|8 separates contacts886 and 881 in order to reduce the power input to thel solenoid coil to prevent damage thereto from excessive heating.y Thus, after the solenoid plunger has been retracted to open the contacts mentioned, current can still flow to coil 888 by way of lead 8|I, resistance 8I2, and lead 885. Resistance 8|2 reduces the power input to thev solenoid coil to a safe value, although passing sufficient current to maintain the solenoid energized.

Solenoid 884 is also shown in Figures 5, 7, and 8 of the drawings, and accordingly includes an extension 8|8 adapted to engage and push against an arm 8|4 when the solenoid 884 is energized. Arm 8|4 is pivoted as at 8| 5 and has connected to it in any suitable manner an arm 8|6 in the end of which is formed a slot 8H. 'I'he arms on the end of arm 8|6 which form the slot embrace a pin 8| 8 which pivotally connect a pair of toggle arms 8|9 and 828, the former of which is plvotally mounted on shaft |48. The free end of toggle arm 828 has a pin 822 fastened thereto which extends through a slot 828 cut in the top of casing ||8. Thus it will appear that when the solenoid plunger moves upon energization of the solenoid, extension 8|8 (Figure 7) moves to the left to pivot arms 8|4 and 8|6 counterclockwise, causing the toggle joint formed by toggle arms 8|9 and 828 to straighten out to the position shown in Figure '7. This, in turn, causes pin 822 to move to the lower end of slot 828, as viewed in this figure.

The other end of pin 822 (Figure 6) is connected toV a lever 824 pivotally mounted on stud shaft |58. 'I'his lever includes a stop arm 828 which, when solenoid 304 is energized, is moved counterclockwise to the position shown in Figure 6, wherein it engages cam stop I2 |a of the shutter cam |2| when this cam has rotated approximately 180. Rotation of the cam to this extent is sufcient for the shutter leaves to open, and accordingly the shutter is held open when the solenoid 304 is energized. These several parts, which upon actuation hold the shutter cam |2| against further or shutter closing operation, are held in this position until solenoid 304 (Figure 13) is deenergized through operation of intervalometer 292. When the solenoid is thus deenergized, a spring 326 (Figure 7) which is fastened to arm 3|6 pulls arm 3|6 clockwise, as viewed in this iigure, and this movement is transmitted by the toggle joints 3|9 and 320 and pin 322 to lever 324 (Figure 6) causing this latter lever to rock clockwise as viewed in Figure 6, thus to move its stop arm 325 away from cam stop |2|a, permitting the shutter cam |2| to complete its rotation. As f described hereinabove, this latter motion of the shutter cam causes the case drive to trip and the camera to rewind.

In the event that the retard Segments |49 and |59 (Figure 6) happen to be adjusted for slow` speed operation when the camera is operated for time exposure, they might impose sufcient drag on the shutter so that the shutter springs power would be insuilicient to close,l the shutter after being held open by the time exposure mechanism just described. Accordingly we provide a pin 321 (Figure 5) on one end of the solenoid plunger 3|0 which upon energization of the solenoid engages one end of a lever 328 to rock this lever counterclockwise. This lever is attached to shaft |18 and accordingly when the lever is rocked,

fshaft |78 (Figure 4), lever |16, link |69, arm |58,

and shaft |66 are moved in such manner as to move the retard segments |49 and |59 out of the path of cam |52 on shutter cam |2|, thus leaving cam |2| absolutely free to close when the solenoid is deenergized.

It accordingly may be seen that we have provided a camera which fullls the several objects set forth hereinabove in a thoroughly practical and efficient manner.

As many possible embodiments may be made of the above inventiony and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to bel interpreted as illustrative and not in a limiting sense.

We claim:

1. In a camera, in combination, a shutter, shutter operating mechanism, means including a trip for actuating said operating mechanism, magnetic means for retaining said trip in shutter holding position and adapted upon deenergization to release said trip, magnetic means adapted when energized to stop said shutter operating mechanism during its operation at a position wherein the shutter is held open, and means for simultaneously deenergizing said first magnetic means and energizing said second magnetic means to open said shutter and hold it open.

2. In a camera, in combination, a shutter, shutter operating mechanism, means including a trip for actuating said operating mechanism', magnetic means for retaining said trip in shutter holding position and adapted upon deenergization to release said trip, magnetic means adapted when energized to stop said shutter operating mechanism during its operation at a position wherein the shutter is held open, means for simultaneously deenergizing said first magnetic means and energizing said second magnetic means to open said shutter and hold it open, and means for simultaneously deenergizing said second magnetic means and energizing said ilrst magnetic means to close said shutter and hold it closed.

3. In a camera, in combination, a shutter. shutter operating mechanism, means operable for retarding the operation of said mechanism to regulate the period of time said shutter remains open, means including a trip for actuating said operating mechanism, magnetic means for retaining said trip in shutter holding position and adapted upon deenergization to release said trip, magnetic means adapted when energized to stop said shutter operating mechanism during its operation at a position wherein the shutter is held open, means for simultaneously deenergizing said first magnetic means and energizing said second magnetic means to open said shutter and hold it open, and means operated by said second magnetic means upon energization thereof for disabling said retarding means.

4. In a camera, in combination, a cone, driving mechanism mounted on said cone, an assembly including a shutter and shutter operating mechanism detachably mounted within said cone, means forming driving connections between said driving mechanism and said assembly, said shutter operating mechanism including a rotatable shaft and a rst stop connected to the shutter, a spring associated with said shaft for opening and closing the shutter, a second stop secured to one end of said spring and also fastened to said shaft, magnetic means mounted on said assembly and normally energized for holding lsaid-second stop in spring retaining position, a' cam freely mounted on said shaft and secured to the other end of said spring so as to rotate when the spring is rewound, lever means associated with said cam and adapted to be rocked thereby, and a holding member connected to said levermeans and associated with said first stop, said holding member adapted to be rocked out of its stop holding position during rotation of said cam as said spring is rewound after exposure operation of the shutter.

5. Apparatus according to claim 4 wherein said driving mechanism includes a cyclically operated motor connected to said spring through one of said driving connections for tensioning said spring, and means associated with said shaft and effective upon rotation thereof during exposure operation of the shutter for causing energization of said motor to rewind said spring.

6. Apparatus according to claim 4 wherein said driving mechanism includes a cyclically operated motor connected to said spring through one of said driving connections for tensioning said spring, a cam secured to said shaft so as to rotate therewith during exposure operation of the shutter, and means connected to another of said driving connections and operated by said last-mentioned cam for effecting energization of said motor to rewind said spring.

7. In a camera, in combination, a cone, driving mechanism mounted on said cone, an assembly including a shutter and shutter operating mechanism detachably mounted within said cone, means forming driving connections between said driving mechanism and said assembly, said shutter operating mechanism including a rotatable shaft and a nrst stop connected to the shutter, a spring associated with said shaft for opening and closing the shutter, a second stop secured to one end of said spring and also fastened to said shaft, magnetic means mounted on said assembly and normally energized for holding said second stop` in spring retaining position, a cam freely mounted on said shaft and secured to the other end of said spring so as to rotate when the spring is rewound, lever means associated with said cam and adapted to be rocked thereby. a holding member connected to said lever means and associated with said rst stop, said holding-member adapted to be rocked out of its stop holding position during rotation o'f said cam as said spring is rewound after exposure operation of the shutter, and spring means for normally maintaining said holding member out of holding position relative to said nrst stop.

8. In a camera, in combination, a shutter, shutter operating mechanism, means for actuating said operating mechanism, magnetic means for vacuum tube having a control electrode and a maintaining said actuating means in a position V wherein the shutter is held closed and adapted upon deenergization to release said actuating means to open said shutter, magnetic means adapted when energized to stop said shutter operating mechanism during its operation ai: a position wherein the shutter is held open, and means for simultaneously deenergizing said nrst magnetic means and energizing said second magnetic means to open said shutter and hold -it open.

`9. In a camera, in combination, a shutter, shutter operating' mechanism, means for said operating mechanism, magnetic means for maintaining'sa id actuating means in a position wherein the vshutter is held closed and adapted uponV deenergization to release said actuating means to open said shutter, magnetic means adapted when energized to stop said shutter operating mechanism during its operation at a P081- .tion wherein the shutter is held open, means for simultaneously deenergizingsaid first magnetic current therethrough and accordingly through.

means andenergizing said second means to open said shutter v and hold it open. and means for simultaneously deenergizing said second magnetic means and energizing said first magnetic means to close said shutter and hold it closed.

source of electric power for supplying power through said tube to said energizable means, said circuit also including means responsive to a flash of light for impressing a bias on the control electrode of said tube to stop immediately the flow of current therethrough and accordingly through said energizable means, therebyto deenergize said energizable means and effect shutter operation, that improvement which consists in providing circuit means for bypassing said electric power to said energizable means around said tube while the tube is non-conductive'during its warm up period so that said energizable means may be energized while said tube is warming up.

1l. In a camera wherein energizable means are provided for holding when energized a stop for a spring driven shutter and for releasing said stop when deenergized, said camera also including a circuit for said energizable means includinga vacuum tube having a control electrode and a source of electric power for supplying power through said tube to said energizable means. said circuit also including means responsive to a flash of light for im a bias on the control electrode of said tube to stop immediately the iiow of said energizable means, thereby to deenergize said energizable means'and effect shutter operation,

. that improvement which consists in providing circuit means for bypassing said electric power to said energizable means around said tube while the tube is non-conductive during its warm up period so that said energizable means may be energized while said tube is warming up, and means responsive to said tube becoming conductive for disabling said bypassing means.

IRVING W. DOYLE. Y ALFRED G. NASH. FRANK W. STELLWAGEN. 

